It is indeed a good feature, but many people may not know that there is a graphical expansion to the numbers. Since people think twice before clicking any link, probably its better to give a snapshot of the graph when they hover aver the link.

The graphs are made using the Google Chart API. I just made it pull the data out of his database and then build the necessary URL to produce the graph. You can see the rather unwieldy image link it’s producing in the page source. That link has all the necessary data to produce the graph.

The Chart API is pretty cool, once you get used to it. It can do some really clever things.